Manufacturing process of superconducting wire and retainer for heat treatment

Abstract

It is an object to provide a process for producing a superconducting wire without defects, such as deterioration of characteristics and deformation, in which a superconducting wire having a length of 1 km or more and a high critical electric current density is easily subjected to heat treatment. The first invention comprises a step of inserting a metallic sheath wire, which is formed by filling a superconducting material in a metallic sheath, into a metallic tube having an inner diameter larger than an outer diameter or a width of the metallic sheath wire; and a step of conducting heat treatment under such a condition in that the superconducting wire is wound to overlap a cylindrical fixture to prevent contact with each other while controlling the interior of the metallic tube. The second invention uses a ceramic board on the heat treatment of a pancake formed by winding the metallic sheath wire on a core. Since the binder of the ceramic board disappears, and the powder or fibers are in a freely movable state, the ceramic board does not restrict shrinkage and expansion of the wire, so as not to cause deformation of the wire. Thus, a long length wire having a length of 1 km or more can be subjected to heat treatment. The characteristics can be improved by conducting the heat treatment under the prescribed conditions of oxygen partial pressure and temperature.

Dependencies are inferred from the claim text.